Acute erythema nodosum
Bowel-associated dermatosis–arthritis syndrome (bowel bypass syndrome, bowel bypass syndrome without bowel bypass, intestinal bypass arthritis–dermatitis syndrome)
Marshall syndrome
Neutrophilic dermatosis of the dorsal hands (pustular vasculitis of the dorsal hands)
Neutrophilic eccrine hidradenitis
Pyoderma gangrenosum
Pyogenic arthritis–pyoderma gangrenosum–acne syndrome (PAPA syndrome)
Rheumatoid neutrophilic dermatitis (rheumatoid neutrophilic dermatosis)
Superficial granulomatous pyoderma
Sweets syndrome (acute febrile neutrophilic dermatosis)
Sweets syndrome-like dermatosis
Vesicopustular dermatosis

Recalcitrant palmoplantar eruptions
Recalcitrant palmoplantar eruptions are skin conditions of the palms and soles which are resistant to treatment. Dermatitis repens (acrodermatitis continua, acrodermatitis continua of Hallopeau, acrodermatitis continua suppurativa Hallopeau, acrodermatitis perstans, dermatitis repens Crocker, Hallopeaus acrodermatitis, Hallopeaus acrodermatitis continua, pustular acrodermatitis)
Infantile acropustulosis (acropustulosis of infancy)
Palmoplantar pustulosis (persistent palmoplantar pustulosis, pustular psoriasis of the Barber type, pustular psoriasis of the extremities, pustulosis of palms and soles, pustulosis palmaris et plantaris)
Pustular bacterid

Resulting from errors in metabolism
Skin conditions resulting from errors in metabolism are caused by enzymatic defects that lead to an accumulation or deficiency of various cellular components, including, but not limited to, amino acids, carbohydrates, and lipids.
Adult T-cell leukemia/lymphoma
Angiocentric lymphoma (extranodal natural killer cell lymphoma, nasal-type NK lymphoma, NK/T-cell lymphoma, polymorphic/malignant midline reticulosis)
Angioimmunoblastic T-cell lymphoma (angioimmunoblastic lymphadenopathy with dysproteinemia)
Blastic NK-cell lymphoma
CD30+ cutaneous T-cell lymphoma (primary cutaneous anaplastic large cell lymphoma)
Cutaneous lymphoid hyperplasia (borrelial lymphocytoma, lymphadenosis benigna cutis, lymphocytoma cutis, pseudolymphoma, pseudolymphoma of Spiegler and Fendt, sarcoidosis of Spiegler and Fendt, Spiegler–Fendt lymphoid hyperplasia, Spiegler–Fendt sarcoid) 
Cutaneous lymphoid hyperplasia with bandlike and perivascular patterns
Cutaneous lymphoid hyperplasia with nodular pattern (nodular pattern of cutaneous lymphoid hyperplasia)
Diffuse large B-cell lymphoma (primary cutaneous large B-cell lymphoma)
Granulocytic sarcoma (chloroma, myeloid sarcoma)
Granulomatous slack skin
Hairy-cell leukemia
Hodgkins disease
Ichthyosis acquisita (acquired ichthyosis)
IgG4-related skin disease
Intravascular large B-cell lymphoma (angiotropic large cell lymphoma, intralymphatic lymphomatosis, intravascular lymphomatosis, malignant angioendotheliomatosis)
Jessner lymphocytic infiltrate of the skin (benign lymphocytic infiltration of the skin, Jessner lymphocytic infiltration of the skin, Jessner–Kanof lymphocytic infiltration of the skin, lymphocytic infiltrate of Jessner)
Kikuchis disease (histiocytic necrotizing lymphadenitis)
Large plaque parapsoriasis (parapsoriasis en plaques)
Lennert lymphoma (lymphoepitheliod lymphoma)
Leukemia cutis
Lymphoma cutis
Lymphomatoid granulomatosis
Lymphomatoid papulosis
Malignant histiocytosis (histiocytic medullary reticulosis)
Marginal zone B-cell lymphoma
Mucosa-associated lymphoid tissue lymphoma
Mycosis fungoides
Non-mycosis fungoides CD30− cutaneous large T-cell lymphoma
Nonspecific cutaneous conditions associated with leukemia (leukemid)
Pagetoid reticulosis (acral mycoses fungoides, localized epidermotropic reticulosis, mycosis fungoides palmaris et plantaris, unilesional mycosis fungoides, Woringer–Kolopp disease)
Pityriasis lichenoides chronica (chronic guttate parapsoriasis, chronic pityriasis lichenoides, dermatitis psoriasiformis nodularis, parapsoriasis chronica, parapsoriasis lichenoides chronica)
Pityriasis lichenoides et varioliformis acuta (acute guttate parapsoriasis, acute parapsoriasis, acute pityriasis lichenoides, Mucha–Habermann disease, parapsoriasis acuta, parapsoriasis lichenoides et varioliformis acuta, parapsoriasis varioliformis)
Plasmacytoma 
Plasmacytosis
Pleomorphic T-cell lymphoma (non-mycosis fungoides CD30− pleomorphic small/medium-sized cutaneous T-cell lymphoma)
Polycythemia vera (erythremia)
Primary cutaneous follicular lymphoma (follicular center cell lymphoma, follicular center lymphoma)
Primary cutaneous immunocytoma
Primary cutaneous marginal zone lymphoma
Retiform parapsoriasis
Secondary cutaneous CD30+ large cell lymphoma
Sézary syndrome
Sinus histiocytosis with massive lymphadenopathy (Rosai–Dorfman disease)
Subcutaneous T-cell lymphoma (panniculitis-like T-cell lymphoma)
Vesiculopustular eruption and leukemoid reaction in Down syndrome

Melanocytic nevi and neoplasms
Melanocytic nevi and neoplasms are caused by either a proliferation of (1) melanocytes, or (2) nevus cells, a form of melanocyte that lack dendritic processes.