TABLE 1: DIFFERENTIAL DIAGNOSIS OF THE RETICULATED PIGMENTARY DISORDERS
|
Dowling Degos Disease (DDD) |
Galli-Galli Disease* (GGD) |
Reticulated Acropigmentation of Kitamura (RAPK) |
Dyschromatosis Symmetrica Hereditaria ** (DSH) |
Dyschromatosis Universalis Hereditaria (DUH) |
Pigmentary morphology |
Brown-black macules |
Same as DDD; but some lesions may be palpable |
Brown-black macules but some may be atrophic and depressed |
Intermingled hyper- and hypo-pigmented macules |
Intermingled hyper- and hypopigmented macules |
Distribution |
Flexural: axillae, neck, antecubital & popliteal fossae |
Same as DDD |
Dorsal hands and feet; may slowly become generalized in adult life |
Dorsal hands and feet; occasionally on the face |
Widely disseminated on trunk, limbs and face |
Histology |
Elongation and branching of rete ridges; lower third of rete tips are darkly pigmented; no increase in melanocytes |
Same as DDD; but acantho- lysis is present |
Epidermal atrophy; little or no elongation of the rete ridges; increased basal layer pigmentation but no increase in number of melanocytes |
Increased pigment in basal layer of hyper-pigmented spots; decreased pigment and sometimes decreased melanocytes in basal layer of hypopigmented spots |
Similar to DSH but pigment incontinence may be present in the hyperpigmented macules |
Other abnormalities that may be associated |
Acne-like facial pits; prominent comedones; follicular papules; hidradenitis suppurativa |
Likely similar to DDD but not well documented in the few cases of GGD so far reported |
Small pits and a broken rete ridge pattern on palms, soles and digits; pits may be present on the dorsal surface of digits |
None definitively documented |
None definitively documented |
Gene Defect |
Keratin 5 |
Keratin 5 |
Unknown |
ADAR1*** |
KITLG**** |
* Galli-Galli disease and DDD are variants of the same disease.
** Synonym: reticulated acropigmentation of Dohi
*** ADAR1, gene for adenosine deaminase acting on RNA 1; also known as DSRAD
**** KITLG, c-Kit ligand